WHAT HAPPENED? Tom Coughlin gives a perplexed look during the Giants' 26-6 loss to the Broncos last night in Denver. The Giants came up small when it mattered most, according to Post columnist Steve Serby Photo: Getty Images

DENVER — The Thanksgiving turkey wore white uniforms with red numerals and blue helmets last night and the Broncos carved it up.

Meet your New York Giants: The Rocky Horror Picture Show of a football team.

When Broncos 26, Giants 6 mercifully ended, Chris Snee was told that it did not look like New York Giants football.

“You’re exactly right,” he said. “That was as far from New York Giant football that I’ve seen around here in a long time.”

It wasn’t the altitude that sucked the air out of the 6-5 Giants. It’s the attitude. They don’t have any. They don’t have any meanness, they don’t have any toughness and they don’t have any clue, and if they keep playing like this, they will not have any hope.

Snee was asked what was missing.

“It seemed like there was no fire,” he said. “It just flat-out seemed like they wanted it more. You’d be hard-pressed to find one or two games where you could say that about this team.”

Snee was told that was inexcusable in a game of this magnitude.

“Absolutely,” he said. “There’s just so much on the line. Definitely a huge step backwards.”

True Blue gladiators of yesteryear would have treated these free-falling Broncos like a sparring partner to get mean and lean for the heavyweight showdowns that await them against the Cowboys and Eagles.

This was an opportunity for the Giants to remember how to be road warriors again, how to build a snowball of momentum and roll it into December and beyond.

Even Eli Manning (28 passing yards in the first half) caught whatever disease has stricken the defense once feared as Big Blue.

This was a stage on which True Blue gladiators of yesteryear would have beaten the ever-loving stuffing out of the Kyle Orton Broncos. They would have bullied them over 60 minutes on both sides of the ball. They would have kicked sand in their face. They would have hit them in the mouth and kept hitting them and snorted killer instinct. They would have scared the quarterback more than they have been scaring their fans.

Coach Tom Coughlin saw a ragtag outfit that could not run the ball (16 carries for 57 yards) and could not stop the run, among other things, and groaned: “That’s where football starts to me.”

Orton’s 17-yard touchdown pass to a wide-open Brandon Stokley put the New York Football Turkeys out of their misery with 10:15 left.

“We still gave up too many easy plays in coverage,” Coughlin said.

Snee stood in shock at his locker.

“I can’t believe that we weren’t able to move the ball on that defense and to score enough points to win that game,” Snee said.

No one wants to hear anymore about any communication problems, or the painstaking transition from defensive coordinator Steve Spagnuolo to Bill Sheridan, or the loss of Antonio Pierce. The game plan was clear: give the feuding Broncos a reason to implode again. Dictate to Orton, a mediocrity saddled with a suspect ankle, and squeeze the hope out of his offense early.

True Blue Giants would have smelled blood. Danny Clark sacked Orton for a 10-yard loss on his first play from scrimmage. The Giants, kings of matador tackling, never sacked him again.

Even after Terrell Thomas tried to change the momentum in the third quarter with an interception and 24-yard return, Manning could not get his team in the end zone. Brandon Jacobs, who looked like he was running with 10-pound weights attached to his ankles, lost three yards around left end. On third-and-13, Manning threw for six yards to Steve Smith. Field goal.

Manning, down 16-3, found Steve Smith with a 30-yard strike down the left sideline against Alpohonso Smith. Then got 13 on a screen to Jacobs, to the Broncos 20. Then settled for another field goal.

“We just didn’t make enough plays,” Manning said.

Proof that the Giants defense is no longer feared: Josh McDaniels, fourth-and-5 at the Giants’ 29, disdained the field goal for a play he liked much better — a 22-yard completion from Orton to a wide-open Tony Scheffler.

Coughlin turned to D.J. Ware for a spark early in the second quarter. Ware gained eight yards on his third carry and then lost the ball. Clark Haggan forced the fumble. Dawkins recovered it at the Giants’ 38. Brandon Marshall resembled Dennis Rodman going up for the first of his two one-handed catches, and soon it was 13-0, and over, really.

Justin Tuck was asked what was missing.

“I dare say heart,” he said. “It kinda looked that way, but I’m not gonna say that because I don’t believe it, but . . . something was. Until we find an answer, we’re poised to continue to get performances like this.

“That’s not what we want to do.”

Holiday wishes for Plax

On Thanksgiving Day, I found myself thinking of Plaxico Burress behind bars. I thought of his wife, Tiffany, who gave birth earlier this month to a girl, Giavonna. I thought of his 3-year-old son, Elijah.

All Burress had to be thankful for is the fact that he didn’t seriously injure himself, or anyone else inside the Latin Quarter nightclub that fateful night — days after Thanksgiving 2008 — he absent-mindedly toted that Glock into that nightclub. Antonio Pierce, his sidekick that night, wasn’t on the field with his teammates last night because of a bulging disc in his neck, and no one can be sure if his Giants days are gone, too.

But Plaxico Burress’ teammates on Thanksgiving night were not inmates at the Oneida Correctional Facility in Rome, N.Y.

You break the law, you don’t deserve celebrity justice. You did the crime, you pay the time. Or at least a good chunk of it. But I can’t help but feel that one Thanksgiving away from your loved ones, and one New Year’s, is punishment enough for the crime of blatant stupidity.

Burress is scheduled to regain his freedom in June 2011 — at the earliest. He will be 33. Here’s hoping the justice system will consider showing him some mercy so he can be a free man next Thanksgiving.

One suggestion: Tack on the six months to his two years of probation he is due to serve once he is scheduled to be freed.

“I want to go see him but, if I was him, I’m not sure if I’d want to see. . . . I might just want to detach myself from that situation, so that’s the bit of the trepidation involved with going to see him,” Osi Umenyiora said.

Umenyiora was asked what he would say to his old teammate.

“Just keep your head up, man,” he said. “When he gets out, he’s gonna still have time to play football as an outstanding football player obviously. Somebody’s gonna give him a shot, and I’m praying for him.”

Umenyiora said that Brandon Jacobs spoke with Burress about a month ago — about a month into his sentence. Tuck’s wife, Lauren, has spoken with Tiffany Burress.

“[Jacobs] said he was all right; he said he was doing OK,” Umenyiora said.